Problem: $ { {-3} \times \left[\begin{array}{r}{3} \\ {1} \\ {-2}\end{array}\right] = {?} } $
Explanation: To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{r}{-3}\times{3} \\ {-3}\times{1} \\ {-3}\times{-2}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{r}{-9} \\ {-3} \\ {6}\end{array}\right]}$